Messages in this thread | | | Date | Fri, 26 Nov 2010 08:53:55 +0530 | From | Balbir Singh <> | Subject | Re: [PATCH] [BUG] memcg: fix false positive VM_BUG on non-SMP |
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* KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> [2010-11-24 09:23:37]:
> On Tue, 23 Nov 2010 23:52:44 +0100 > Johannes Weiner <hannes@cmpxchg.org> wrote: > > > On Tue, Nov 23, 2010 at 02:22:47PM -0800, Andrew Morton wrote: > > > On Tue, 23 Nov 2010 22:02:55 +0100 > > > Johannes Weiner <hannes@cmpxchg.org> wrote: > > > > > > > On Tue, Nov 23, 2010 at 12:16:06PM -0800, Andrew Morton wrote: > > > > > On Tue, 23 Nov 2010 15:48:50 +0200 > > > > > "Kirill A. Shutsemov" <kirill@shutemov.name> wrote: > > > > > > > > > > > ------------[ cut here ]------------ > > > > > > kernel BUG at mm/memcontrol.c:2155! > > > > > > > > > > This bug has been there for a year, from which I conclude people don't > > > > > run memcg on uniprocessor machines a lot. > > > > > > > > > > Which is a bit sad, really. Small machines need resource control too, > > > > > perhaps more than large ones.. > > > > > > > > Admittedly, this patch is compile-tested on UP only, but it should be > > > > obvious enough. > > > > > > > > --- > > > > From: Johannes Weiner <hannes@cmpxchg.org> > > > > Subject: [patch] memcg: fix page cgroup lock assert on UP > > > > > > > > Page cgroup locking primitives use the bit spinlock API functions, > > > > which do nothing on UP. > > > > > > > > Thus, checking the lock state can not be done by looking at the bit > > > > directly, but one has to go through the bit spinlock API as well. > > > > > > > > This fixes a guaranteed UP bug, where asserting the page cgroup lock > > > > bit as a sanity check crashes the kernel. > > > > > > > > > > hm, your patch is the same as Kirill's, except you named it > > > page_is_cgroup_locked() rather than is_page_cgroup_locked(). I guess > > > page_is_cgroup_locked() is a bit better. > > > > I had not sorted by threads and somehow assumed this was another > > forward from you of a bugzilla report or something. I didn't see > > Kirill's patch until now. Sorry! > > > > Reviewed-by: Johannes Weiner <hannes@cmpxchg.org> > > Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujtisu.com> >
Great catch! Thanks
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
-- Three Cheers, Balbir
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